A number of tasks can be characterized as sorting problems in which a collection of objects having similar sizes and shapes are to be sorted manually into groups based on a label or other indicator on each object. For example, in histopathology laboratories, specimens that have been prepared from patient tests and mounted on microscope slides must be sorted into trays for viewing by various pathologists who work in the laboratory. A tray typically includes the slides for a particular patient in an order that depends on the particular pathologist who is assigned to view the slides and on the type of samples on the slides. Slide sorting is one of the time consuming and manual tasks in histopathology laboratories, and is not easily automated. In addition to manually organizing slides into folders or trays, descriptive reports must also be included prior to distribution to pathologists for diagnosis. Slide sorting is a major bottleneck in histopathology laboratory workflows.
Fully automated slide sorting systems in which robots sort the slides and place them in the trays present challenges because of the high cost of replacing a slide that is damaged in the automated handling. In many cases, replacing a slide is impossible, since the original patient sample is depleted and obtaining another sample requires surgery or other invasive procedures on the patient. Hence, a fully automated sorting system has not found widespread acceptance.
In other sorting problems, robotic solutions present problems because the shape of the samples being sorted does not lend itself to automated handling. For example, if the samples differ markedly in shape providing a robotic device for picking up the objects and placing them in the final container presents challenges. Similarly, if a number of different sample types are to be sorted at different times, the setup time for changing the manipulator on the robot can make such systems impractical. Similarly, fragile samples can present handling problems for robotic systems.